Final answer:
The nurse would assign a rating of A. 2 on the sedation scale, indicating that the client is awake and alert.
Step-by-step explanation:
The nurse would assign a rating of A. 2 on the sedation scale. This rating indicates that the client is awake and alert, which is the desired level of sedation for pain control with opioid analgesia. The sedation scale ranges from 0 to 10, with 0 representing no sedation and 10 representing extreme sedation. A rating of 2 suggests that the client is not overly sedated and can fully participate in activities and communicate effectively.